Fabrication process and system for copper interconnects

Abstract

Additive manufacturing techniques are described. In one example, a method includes printing, using a printable copper ink, a layer of copper onto a substrate, applying a photonic sintering process to cure the layer of copper to produce a cured layer of copper, repeating, in an alternating manner, the printing and the photonic sintering process to individually print and cure a plurality of additional layers of copper over the cured layer of copper to produce a copper pillar having a selected height, and after forming the copper pillar to the selected height, depositing, onto the substrate, a dielectric material at least partially surrounding the copper pillar.

What is claimed is: 
     
         1 . A method comprising:
 printing, using a printable copper ink, a layer of copper onto a substrate;   applying a photonic sintering process to cure the layer of copper to produce a cured layer of copper;   repeating, in an alternating manner, the printing and the photonic sintering process to individually print and cure a plurality of additional layers of copper over the cured layer of copper to produce a copper pillar having a selected height; and   after forming the copper pillar to the selected height, depositing, onto the substrate, a dielectric material at least partially surrounding the copper pillar.   
     
     
         2 . The method of  claim 1 , wherein printing the layer of copper is performed using an aerosol jet printer. 
     
     
         3 . The method of  claim 2 , wherein depositing the dielectric material comprises printing the dielectric material using the aerosol jet printer. 
     
     
         4 . The method of  claim 1 , wherein printing the dielectric material is performed using a dielectric epoxy ink. 
     
     
         5 . The method of  claim 1 , wherein the printable copper ink comprises a plurality of copper nanoparticles dispersed in a carrier fluid. 
     
     
         6 . The method of  claim 5 , wherein the carrier fluid comprises one or more organic solvents. 
     
     
         7 . The method of  claim 1 , wherein applying the photonic sintering process comprises photonically sintering the layer of copper for a duration in a range of 1 to 10 milliseconds. 
     
     
         8 . The method of  claim 1 , wherein printing the layer of copper comprises printing the layer of copper having a thickness in a range of 1-10 micrometers. 
     
     
         9 . A method comprising:
 printing, using a printable copper ink, a plurality of layers of copper onto a substrate, individual layers of copper being stacked on top of one another to produce a copper pillar having a selected height;   after printing each individual layer of copper, and prior to printing a subsequent layer of copper, curing the individual layer of copper, such that the plurality of layers of copper are individually printed and cured in sequence; and   after forming the copper pillar to the selected height, depositing, onto the substrate, a dielectric material at least partially surrounding the copper pillar.   
     
     
         10 . The method of  claim 9 , wherein printing the plurality of layers of copper is performed using an aerosol jet printer. 
     
     
         11 . The method of  claim 10 , wherein depositing the dielectric material comprises printing a dielectric epoxy ink using the aerosol jet printer. 
     
     
         12 . The method of  claim 9 , wherein printing the plurality of layers of copper comprises printing the individual layers of copper each with a thickness of approximately 5 micrometers. 
     
     
         13 . The method of  claim 9 , wherein curing the individual layer of copper comprises photonically sintering the individual layer of copper. 
     
     
         14 . The method of  claim 13 , wherein photonically sintering the individual layer of copper comprises photonically sintering the individual layer of copper for a duration in a range of 1 to 10 milliseconds. 
     
     
         15 . The method of  claim 9 , wherein curing the individual layer of copper is performed using a near-infrared laser. 
     
     
         16 . A computer program product comprising one or more non-transitory machine-readable mediums having instructions encoded thereon that when executed by at least one processor cause a process to be carried out for producing a copper interconnect using additive manufacturing, the process comprising:
 controlling a printing apparatus to print, using a printable copper ink, a layer of copper onto a substrate;   controlling a curing apparatus to cure the layer of copper;   repeating, in an alternating manner, the acts of controlling the printing apparatus to print the layer of copper and controlling the curing apparatus to cure the layer of copper to individually print and cure a plurality of additional layers of copper over the layer of copper to produce a copper pillar having a selected height; and   after the copper pillar is formed to the selected height, controlling the printing apparatus to print, onto the substrate, a dielectric material at least partially surrounding the copper pillar.   
     
     
         17 . The computer program product of  claim 16 , wherein controlling the curing apparatus to cure the layer of copper comprises controlling a photonic sintering apparatus to photonically sinter the layer of copper. 
     
     
         18 . The computer program product of  claim 17 , wherein controlling the photonic sintering apparatus comprises controlling one or more parameters of the photonic sintering apparatus, the one or more parameters including a number of pulses applied to cure the layer of copper, a pulse width of individual pulses applied to cure the layer of copper, a duty cycle of the individual pulses applied to cure the layer of copper, and/or a control voltage applied to generate the pulses applied to cure the layer of copper. 
     
     
         19 . An apparatus for producing a copper interconnect, the apparatus comprising:
 a printing system configured to print a printable copper;   a curing system configured to cure copper printed by the printing system; and   a controller configured to
 cause (a) the printing system to print a layer of copper onto a substrate and (b) the curing system to cure the layer of copper, so as to provide a cured copper layer, 
 cause repeating of (a) and (b) one or more times to produce a copper pillar of a selected height, and 
 after the copper pillar is formed to the selected height, cause the printing system to print a dielectric material at least partially surrounding the copper pillar. 
   
     
     
         20 . The apparatus of  claim 19 , wherein the curing system comprises a photonic sintering system. 
     
     
         21 . The apparatus of  claim 20 , wherein the controller is configured to control one or more parameters of the photonic sintering system to cure the layer of copper, the one or more parameters including a number of pulses applied to cure the layer of copper, a pulse width of individual pulses applied to cure the layer of copper, a duty cycle of the individual pulses applied to cure the layer of copper, and/or a control voltage applied to generate the pulses applied to cure the layer of copper. 
     
     
         22 . The apparatus of  claim 19 , wherein the printing system comprises an aerosol jet printer. 
     
     
         23 . The apparatus of  claim 22 , wherein the printable copper comprises a printable copper ink including a plurality of copper nanoparticles dispersed in a carrier fluid, and wherein the carrier fluid comprises one or more organic solvents. 
     
     
         24 . The apparatus of  claim 19 , wherein the controller is configured to control the printing system to print the layer of copper with a thickness of approximately 5 micrometers.